1. Field
The present invention relates generally to power saws, and more specifically to minimizing dust dispersion in power saws having rotating cutting blades.
2. Description of Related Art
During various construction, manufacturing and assembly operations, pieces of material such as wood, plastic and metal (i.e. work pieces) must be cut to exact lengths, shapes and dimensions. In many instances, power equipment such as miter saws are used to accomplish these tasks. During cutting operations, a user is typically positioned in front of the saw. Miter saws typically have both a fixed blade guard and a movable blade guard. The fixed blade guard remains fixed relative to the rotating cutting blade and serves to cover an upper portion of the blade during cutting operations. When the user is standing in the front of the miter saw, the blade rotates toward the user at the front end of the saw, which generates air flow toward the front end of the saw. This air flow tends to disperse saw dust that has accumulated on top of the table and other surfaces, and directs some of this dust towards the user. Although the movable blade guard shields the user somewhat, the air flow generated by the rotating blade still causes significant dust dispersion.
FIG. 1 shows a prior art miter saw having a fixed blade guard 26′ that covers a top side of a rotatable cutting blade 12′. At the front end of the blade guard, the inner walls of the guard are spaced from the cutting blade, which allows air flow to freely exit from the front end of the guard. As noted above, this configuration results in extensive scattering of the dust generated during cutting operations and impedes the efficient collection of saw dust.
There have been a number of efforts directed to improving dust collection and/or limiting scattering of dust. For example, commonly assigned U.S. Pat. No. 7,222,560, the disclosure of which is hereby incorporated by reference herein, discloses a miter saw having a dust collector flap secured to the rear of an upper blade guard. In one embodiment, the flap has at least one slot formed therein so that the flap may conform to or easily pass over an obstruction (e.g. a work piece) that engages the dust collector flap.
In spite of the above advances, there remains a need for improved systems, devices and methods for controlling air flow in power saws to thereby reduce dust scattering and/or improve dust collection.